For the second time in two years, a rocket glitch sent a NASA global warming satellite to the bottom of the sea Friday, a $424 million debacle that couldn't have come at a worse time for the space agency and its efforts to understand climate change.

Mankind may have unleashed the sixth known mass extinction in Earth's history, according to a paper released by the science journal Nature.

Climate change is not only making the planet warmer, it is also making snowstorms stronger and more frequent, US scientists said on Tuesday.

You'll never look at hummingbirds the same again. The Pentagon has poured millions of dollars into the development of tiny drones inspired by biology, each equipped with video and audio equipment that can record sights and sounds.

Scroungy and street smart, Moscow's 26,000 stray dogs roam the Russian capital, bedding down in subway stations and even learning to ride the trains. But some are aggressive, traveling in packs and attacking people.

Even a regional nuclear war could spark "unprecedented" global cooling and reduce rainfall for years, according to U.S. government computer models. Widespread famine and disease would likely follow, experts speculate.

Discovery, the world's most traveled spaceship, thundered into orbit for the final time Thursday, heading toward the International Space Station on a journey that marks the beginning of the end of the shuttle era.

More than 150 are feared dead after a major earthquake hit Christchurch, one of New Zealand's biggest cities, in what the prime minister described "New Zealand's darkest day".